A source close to the consultations said the Greek government had asked JP Morgan to come up with a plan for an asset protection scheme and the Greek central bank also had a plan on how to tackle the banks' mountain of bad loans.

"Both the central bank and the government are looking at initiatives to help banks reduce their non-performing loan portfolios," the source told Reuters.

The JP Morgan plan would not necessarily rival that put forward by the central bank, the source added. They could complement each other.

Another source said the central bank's proposal had been presented to the Greek government and to the country's international lenders and was expected to be presented publicly in the coming days.

The HFSF (Hellenic Financial Stability Fund), which holds stakes in Greek banks after taking part in three recapitalisations, was reported to have proposed its own protection scheme earlier in the year.

Bad loans are the biggest challenge facing the Greek banking sector.

The plans are the latest attempt to tackle the conundrum of what to do with a pile of sour loans on banks' balance sheets, inhibiting credit and depriving the economy of a potential source of growth.

Banks have agreed with European Central Bank regulators to take steps to shrink bad loans to 64.6 billion euros by the end of 2019. By the end of June, they stood at 88.6 billion euros, or 47.6 percent of banks' overall loan book.

The sources confirmed a Bloomberg report saying that under the central bank's plan, banks would transfer about half of their deferred tax claims to a special purpose vehicle. The vehicle will then sell bonds and use the proceeds to buy some 42 billion euros of bad loans from the lenders, the report said, citing people familiar with the matter.

Yiannis Stournaras, the central bank governor, told a conference in Geneva on Tuesday that efficient management of bad loans was of "utmost importance" to banking sector stability.

(Writing by Michele Kambas; Editing by Adrian Croft and Edmund Blair)

By Lefteris Papadimas and Renee Maltezou